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- Triggering the TCR developmental checkpoin activates a therapeutically targetable tumor suppressive pathway in T-cell leukemiaPublication . Trinquand, A.; Rodrigues Dos Santos, Nuno; Tran Quang, C.; Belhocine, M.; Jesus, C. da Costa de; Lhermitte, L.; Tesio, M.; Dussiot, M.; Cosset, F. L.; Verhoeyen, E.; Pflumio, F.; Ifrah, N.; Dombret, H.; Spicuglia, S.; Chatenoud, L.; Gross, David-Alexandre; Hermine, Olivier; Macintyre, E.; Ghysdael, Jacques; Asnafi, V.Cancer onset and progression involves the accumulation of multiple oncogenic hits, which are thought to dominate or bypass the physiologic regulatory mechanisms in tissue development and homeostasis. We demonstrate in T-cell acute lymphoblastic leukemia (T-ALL) that, irrespective of the complex oncogenic abnormalities underlying tumor progression, experimentally induced, persistent T-cell receptor (TCR) signaling has antileukemic properties and enforces a molecular program resembling thymic negative selection, a major developmental event in normal T-cell development. Using mouse models of T-ALL, we show that induction of TCR signaling by high-affi nity selfpeptide/MHC or treatment with monoclonal antibodies to the CD3ε chain (anti-CD3) causes massive leukemic cell death. Importantly, anti-CD3 treatment hampered leukemogenesis in mice transplanted with either mouse- or patient-derived T-ALLs. These data provide a strong rationale for targeted therapy based on anti-CD3 treatment of patients with TCR-expressing T-ALL and demonstrate that endogenous developmental checkpoint pathways are amenable to therapeutic intervention in cancer cells.
- Context-dependent roles for lymphotoxin-beta receptor signaling in cancer developmentPublication . Fernandes, Mónica T.; Dejardin, Emmanuel; Rodrigues Dos Santos, NunoThe LT alpha(1)beta(2) and LIGHT TNF superfamily cytokines exert pleiotropic physiological functions through the activation of their cognate lymphotoxin-beta receptor (LT beta R). Interestingly, since the discovery of these proteins, accumulating evidence has pinpointed a role for LT beta R signaling in carcinogenesis. Early studies have shown a potential anti-tumoral role in a subset of solid cancers either by triggering apoptosis in malignant cells or by eliciting an anti-tumor immune response. However, more recent studies provided robust evidence that LT beta R signaling is also involved in diverse cell-intrinsic and microenvironment-dependent pro-oncogenic mechanisms, affecting several solid and hematological malignancies. Consequently, the usefulness of LT beta R signaling axis blockade has been investigated as a potential therapeutic approach for cancer. Considering the seemingly opposite roles of LT beta R signaling in diverse cancer types and their key implications for therapy, we here extensively review the different mechanisms by which LT beta R activation affects carcinogenesis, focusing on the diverse contexts and different models assessed. (C) 2016 Elsevier B.V. All rights reserved.
- NF-kappa B-dependent RANKL expression in a mouse model of immature T-cell leukemiaPublication . Fernandes, Mónica T; Caroco, Lara S.; Pacheco-Leyva, Ivette; R. dos Santos, NunoActivation of the receptor activator of nuclear factor-kappa B (RANK) by its ligand (RANKL) is involved in both solid and hematological malignancies, including multiple myeloma, acute myeloid leukemia and B-cell leukemia. Although RANKL expression has been described in normal T cells, a potential role in T-cell leukemia remains undefined. Here, we used a model of immature T-cell leukemia/lymphoma, the TEL-JAK2 transgenic mice, to assess RANKL expression in leukemic cells and its regulatory mechanisms. We found that Rankl mRNA was significantly overexpressed in leukemic T cells when compared to wild-type thymocytes, their nonmalignant counterparts. Moreover, Rankl mRNA and RANKL surface expression in leukemic cells was induced by T-cell receptor (TCR) signaling activation, dependently on the NFKB signaling pathway. These results indicate that TCR-activated leukemic T cells express high levels of RANKL and are potential inducers of RANK signaling in microenvironmental cells. (C) 2019 Elsevier Inc. All rights reserved.
- P-selectin glycoprotein ligand 1 promotes T cell lymphoma development and disseminationPublication . Pereira, João L.; Cavaco, Patrícia; da Silva, Ricardo C.; Pacheco-Leyva, Ivette; Mereiter, Stefan; Pinto, Ricardo; Reis, Celso A.; Rodrigues Dos Santos, NunoP-selectin glycoprotein ligand-1 (PSGL-1) is a membrane-bound glycoprotein expressed in lymphoid and myeloid cells. It is a ligand of P-, E- and L-selectin and is involved in T cell trafficking and homing to lymphoid tissues, among other functions. PSGL-1 expression has been implicated in different lymphoid malignancies, so here we aimed to evaluate the involvement of PSGL-1 in T cell lymphomagenesis and dissemination. PSGL-1 was highly expressed at the surface of human and mouse T cell leukemia and lymphoma cell lines. To assess its impact on T cell malignancies, we stably expressed human PSGL-1 (hPSGL-1) in a mouse thymic lymphoma cell line, which expresses low levels of endogenous PSGL-1 at the cell surface. hPSGL-1-expressing lymphoma cells developed subcutaneous tumors in athymic nude mice recipients faster than control empty vector or parental cells. Moreover, the kidneys, lungs and liver of tumor-bearing mice were infiltrated by hPSGL-1-expressing malignant T cells. To evaluate the role of PSGL-1 in lymphoma cell dissemination, we injected intravenously control and hPSGL 1-expressing lymphoma cells in athymic mice. Strikingly, PSGL-1 expression facilitated disease infiltration of the kidneys, as determined by histological analysis and anti-CD3 immunohistochemistry. Together, these results indicate that PSGL-1 expression promotes T cell lymphoma development and dissemination to different organs.
- Cdkn2a inactivation promotes malignant transformation of mouse immature thymocytes before the β-selection checkpointPublication . Catarino, Telmo A.; Pacheco-Leyva, Ivette; Kindi, Faiza Al; Ghezzo, Marinella N.; Fernandes, Mónica T.; Costa, Telma; Rodrigues Dos Santos, NunoCDKN2A deletion is the most frequent genetic alteration in T-cell acute lymphoblastic leukemia (T-ALL), occurring across all molecular and immunophenotypic subtypes. CDKN2A encodes two functionally unrelated tumor suppressor proteins, ARF and INK4a, which are critical regulators of cell cycle and proliferation. Arf has been reported to suppress T-ALL development in post−b-selection thymocytes, but whether CDKN2A acts as a tumor suppressor gene in immature, pre−b-selection thymocytes remains to be elucidated. Resorting to a Rag2-deficient model of T-ALL, driven by the ETV6:: JAK2 fusion, we report that Cdkn2a haploinsufficiency at early stages of T-cell development facilitates leukemia development
- NF-κB in T-cell Acute Lymphoblastic Leukemia: Oncogenic functions in Leukemic and in Microenvironmental CellsPublication . Rodrigues Dos Santos, Nuno; Ghezzo, Marinella N.; Da Silva, Ricardo C.; Fernandes, Mónica T.Two main NF-κB signaling pathways, canonical and noncanonical, performing distinct functions in organisms have been characterized. Identification of mutations in genes encoding components of these NF-κB signaling pathways in lymphoid malignancies confirmed their key role in leukemogenesis. T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive malignancy of thymocytes that despite significant therapeutic advances can still be fatal. Although mutations in NF-κB genes have not been reported in T-ALL, NF-κB constitutive activation in human T-ALL and in acute T-cell leukemia mouse models has been observed. Although these studies revealed activation of members of both canonical and noncanonical NF-κB pathways in acute T-cell leukemia, only inhibition of canonical NF-κB signaling was shown to impair leukemic T cell growth. Besides playing an important pro-oncogenic role in leukemic T cells, NF-κB signaling also appears to modulate T-cell leukemogenesis through its action in microenvironmental stromal cells. This article reviews recent data on the role of these transcription factors in T-ALL and pinpoints further research crucial to determine the value of NF-κB inhibition as a means to treat T-ALL.
- Transgenic αβ TCR tonic signaling is leukemogenic while strong stimulation is leukemia suppressivePublication . Catarino, Telmo A.; Pacheco-Leyva, Ivette; Baessa, Marina; Pereira, João L.; Rodrigues dos Santos, NunoThe pre–T cell receptor (TCR) and TCR complexes are frequently expressed in T cell acute lymphoblastic leukemia (T-ALL), an aggressive T cell precursor malignancy. Although mutations in TCR components are infrequent in T-ALL, earlier research indicated that transgenic αβ TCR expression in mouse T cell precursors promoted T-ALL development. However, we recently found that stimulation of TCR signaling in T-ALL induced leukemic cell apoptosis and suppressed leukemia. Our aim was to elucidate if a given αβ TCR complex has a dual role in leukemogenesis depending on the nature of the stimulus. We demonstrate that transgenic expression of the Marilyn αβ TCR, specific for the H-Y male antigen presented by major histocompatibility complex class II, triggers T-ALL development exclusively in female mice. This T-ALL exhibited Notch1 mutations, Cdkn2a copy number loss, and immature immunophenotype, and infiltrated both lymphoid and nonlymphoid organs. Furthermore, leukemic cells expressed surface CD5, a marker of tonic TCR signaling. T-ALL efficiently developed in Rag2-deficient Marilyn transgenic females, indicating that Rag2-mediated recombination is not implicated in this T-ALL model. T-ALL development was also observed in the OT-I TCR transgenic mouse model, but it did not occur when major histocompatibility complex class I was abrogated through genetic inactivation of β2-microglobulin. Remarkably, exposure of Marilyn female T-ALL cells to endogenous agonist antigens in male recipient mice or exogenous peptides in female recipient mice resulted in T-ALL apoptosis and prolonged mouse survival. These findings underscore the dual role of the same αβ TCR complex in T-ALL, in which tonic stimulation is leukemogenic, while strong stimulation suppresses leukemia.